From 53bfcf585b09eb4ac2240f89d1ade77421cd2451 Mon Sep 17 00:00:00 2001 From: Ian Jackson Date: Fri, 14 Jun 2013 16:39:34 +0100 Subject: libxc: introduce xc_dom_seg_to_ptr_pages Provide a version of xc_dom_seg_to_ptr which returns the number of guest pages it has actually mapped. This is useful for callers who want to do range checking; we will use this later in this series. This is part of the fix to a security issue, XSA-55. Signed-off-by: Ian Jackson Reviewed-by: Chuck Anderson v7: xc_dom_seg_to_ptr_pages now always expects pages_out!=NULL. (It seems silly to have it tolerate NULL when all the real callers pass non-NULL and there's a version which doesn't need pages_out anyway. Fix the call in xc_dom_seg_to_ptr to have a dummy pages for pages_out.) v5: xc_dom_seg_to_ptr_pages sets *pages_out=0 if it returns NULL. v4 was: Acked-by: Ian Campbell Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Andrew Cooper --- tools/libxc/xc_dom.h | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'tools/libxc') diff --git a/tools/libxc/xc_dom.h b/tools/libxc/xc_dom.h index ac36600ce7..316c5cbefc 100644 --- a/tools/libxc/xc_dom.h +++ b/tools/libxc/xc_dom.h @@ -294,14 +294,27 @@ void *xc_dom_pfn_to_ptr(struct xc_dom_image *dom, xen_pfn_t first, void xc_dom_unmap_one(struct xc_dom_image *dom, xen_pfn_t pfn); void xc_dom_unmap_all(struct xc_dom_image *dom); -static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom, - struct xc_dom_seg *seg) +static inline void *xc_dom_seg_to_ptr_pages(struct xc_dom_image *dom, + struct xc_dom_seg *seg, + xen_pfn_t *pages_out) { xen_vaddr_t segsize = seg->vend - seg->vstart; unsigned int page_size = XC_DOM_PAGE_SIZE(dom); xen_pfn_t pages = (segsize + page_size - 1) / page_size; + void *retval; + + retval = xc_dom_pfn_to_ptr(dom, seg->pfn, pages); + + *pages_out = retval ? pages : 0; + return retval; +} + +static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom, + struct xc_dom_seg *seg) +{ + xen_pfn_t dummy; - return xc_dom_pfn_to_ptr(dom, seg->pfn, pages); + return xc_dom_seg_to_ptr_pages(dom, seg, &dummy); } static inline void *xc_dom_vaddr_to_ptr(struct xc_dom_image *dom, -- cgit v1.2.3